DE3328133C2 - Powder coatings based on isophorone diisocyanate addition compounds containing uretdione groups and a process for producing matt coatings - Google Patents

Abstract

The invention relates to storage-stable powder coatings based on polyaddition compounds containing a uretdione groups of the formula $ F1 R '= (cyclo) aliphatic C2-14-alkylene radical optionally substituted by alkyl groups, which may contain etherically bound oxygen with a melting point above 130 ° C, preferably above 140 ° C, B hydroxyl-containing polyesters with an average of more than 2 OH groups per molecule, a melting point below 100 ° C and an OH number of 10 to 200 mg KOH / g and C are other common additives, where A and B are used in such amounts that there are 0.5 to 1.3 NCO equivalents of hardener A per 1 OH equivalent B. The powder coatings can be used to produce coatings with matt surfaces.

Description

characterized in that the polyisocyanates A uretdione polyaddition compounds of the isophorone diisocyanate of the formula

OCN- R -

"O

N N -R-NH-C-O-R '-O-C-NH-R

—N N —R —NCO

with R

and R '

optionally substituted by alkyl groups aliphatic or cycloaliphatic C ₂ -alkylene radical, which may optionally contain ether oxygen,

having a melting point of about 13O ⁰ C, wherein η assumes the value, which in the reaction of uretdione groups of isophorone diisocyanate, with diols in an NCO / OH ratio of 1: 0.9 is adjusted, the polyols B containing hydroxyl groups: 0.5 to 1 Polyesters with an average of more than 2 OH groups per molecule, an OH number of 10 to 200 mg KOH / g and a melting point below 100 ^° C., and 0.5 to 1.3 NCO per 1 OH equivalent of polyester B -Equivalents of hardener A come.

2. Powder coatings according to claim 1, characterized in that the polyols B contain hydroxyl groups Polyesters with an OH number of 20 to 100 mg KOH / g.

In that component A has 3 powder coatings according to claim 1 or 2, characterized in that a melting point above 140 ⁰ C.

4. Powder coatings according to Claims 1 to 3, characterized in that η = 3 to 6.

5. Powder coatings according to Claims 1 to 4, characterized in that R 'is a tetramethylene radical stands.

6. Powder coatings according to Claims 1 to 5, characterized in that there are 1 OH equivalent of polyester B 0.9 to 1.1 NCO equivalents of hardener A come.

7. Use of the powder coatings according to claims 1 to 6 for the production of coatings with a matt surface, characterized in that the powder coatings are ^{extruded at a temperature of 80 to 110 °} C, applied to the objects to be coated and at 180 to 200 ^° C hardens within 30 to 15 minutes.

50 55 60 65

For some time now there has been an increasing interest in powder coatings that give a matt surface. The reason for this is mostly of a practical nature. Shiny surfaces require a much higher level of Cleaning as matt surfaces. In addition, for safety reasons it may be desirable avoid highly reflective surfaces.

The simplest principle to obtain a matt surface is to apply the powder coating depending on the extent of the desired matt effect smaller or larger amounts of fillers, such as. B. chalk, finely divided silicon dioxide or barium sulfate. However, these additives have the effect of worsening the technical properties of the paint Film properties such as adhesion, flexibility, impact resistance and chemical resistance.

The addition of substances that are incompatible with the paint, such as B. waxes or cellulose derivatives, It also causes a matt finish, but slight changes during extrusion lead to Fluctuations in surface gloss. The reproducibility of the matt effect is not guaranteed.

At the beginning of the 1970s, powder coatings began to be developed, resulting in different reactivities were used to adjust the matt effect.

It is known from Dutch application 68 06 930 that a matting effect is obtained by that the epoxy resin is cured simultaneously with sulfamic acid and at least 2% trimellitic anhydride.

DE-OS 21 47 653 describes a powder paint mixture with a matt effect that is produced by mechanical mixing of at least two paint powders of different epoxy resin / hardener systems with differing Melting range is established.

The method of DE-OS 22 47 779 is based on a mixture of two paint powder, which is through the Differentiate between the presence and absence of a curing accelerator.

The powder coating system described in Japanese laid-open specification 36 339 (application 08/25/77) for matte coatings is made up of

a) 95 to 20% of a PUR system made of a polyester polyol with a softening point of 65 to 130 ⁰ C and a blocked polyisocyanate as well

b) 5 to 80% of an epoxy acrylate system from an acrylate resin bearing glycidyl ether groups, which with a dicarboxylic acid is hardened.

In DE-OS 23 24 696 a process for the production of coatings with a matt surface is presented, according to which the salt of cyclic amidines with certain polycarboxylic acids for curing epoxy resins is used. In fact, only this one has proven itself due to its excellent lacquer properties Enforce procedures on the market; the process flow has meanwhile been improved (cf. DE-OS 30 26 455).

For the production of coatings that should have extensive weather stability and lightfastness, however, the epoxy resin systems mentioned are not suitable. Powder coatings are used for these purposes based on polyesters containing hydroxy groups and isophorone diisocyanate derivatives. Particularly The isophorone diisocyanate compounds containing uretdione groups, which are used without during curing, have proven themselves released blocking agents get by.

For example, in DE-OS 30 30 539 a powder coating on the basis of a partial or complete blocked polyaddition compound of the formula

X —R -

O
A. O
Il O
Il O
A. N N - R - NH- -C- -0 — R '—0 — C — NH-R - N N -R -X Y Y O O

X = NCO

η > 1

R 'is a divalent aliphatic, cycloaliphatic or araliphatic hydrocarbon radical of the diol,
R "denotes a monoalcohol radical or a primary or secondary monoamine radical with 1 to 30 carbon atoms,

and a polyhydroxyl compound with the following properties:

a) OH functionality (OH-F)

b) mean molecular weight (M)

c) OH number (OH-Z)

d) Viscosity in mPas at 16O ⁰ C (V)

e) Melting point in ° C (melting point)

3.4 <OH-F <7 2000 <M <5000 30 <OH-Z <100 V <100,000 70 <m.p. <120

claimed.

It is not without reason that the OH functionality, viscosity and melting point have been specified so precisely, it works the skilled person assumes that

a) at OH-F <3.4 the required network density is no longer guaranteed (which is reflected in the stability of the Paint precipitates) and that with OH-F> 7 embrittlement occurs,

d) at V> 100,000 mPas the course is impaired,

c) mp <7O ⁰ C, the storage stability is not ensured, and that when mp> 120 ° C is exceeded, the fiir an optimum course desired upper limit.

40

50

65

You can also start from the following polyaddition compounds (cf. DE-OS 30 30 588):

OCN-R -

0 O

N Ν - R - NH - C - - R '- 0 - C --NH-R

- N N - R - NCO

where η, R and R 'have the same meanings as in DE-OS 30 30 539.
In this application, the property limits of the polyols were specified as follows:

a) 2.2 <OH-F <3.5

b) 2000 <M <4500

c) 30 <OH-Z <100 15 d) V <80000

e) 65 <m.p. <120

These limits are also well founded.

a) At OH-F> 3.5 the extrusion process is disturbed; the extruder "freezes".

Sufficient crosslinking is no longer guaranteed at OH-F <2.2.

d), e) At V> 80,000 or Smp> 130, the extrusion process is disrupted. The pigments are not going to be optimal wetted.

Finally, the subject of DE-OS 23 12 391 is a process for the production of powder coatings in which mixtures of dimers and trimers of isocyanates are used. This method does not give the person skilled in the art any instructions going beyond the cited prior art to produce coatings with a matt surface.
The aim of the present invention is to develop powder coatings that are weather-stable and lightfast

Obtain coatings and overcome the disadvantages of the prior art. The powder coatings are said to be uretdione of isophorone diisocyanate, which are used in the production of coatings with a glossy surface have proven to be excellent.

The powder coatings described in claims 1 to 6 have now been found. Subject of this invention is also the use of these powder coatings for the production of matt coatings according to claim 7.

It is surprising that, in contrast to the opinion expressed in EP-OS 0 00 09 694, page 2, line 29, to page 3, line 3, hardeners with a melting point above 130 ^° C., in particular 140 ^° C., are used can. It was unpredictable that the powder coating mixture specified in claim 1 would have coatings with a matt surface

results.

Polyaddition compounds according to DE-OS 30 30 572 are used as hardener A. These consist of Isophorone diisocyanate (IPDI) containing uretdione groups, 98% of which is cleavable in IPDI when heated, and Diols in an NCO / OH ratio of 1: 0.5 to 1: 0.9. According to DE-OS 30 30 513, the uretdione des is obtained IPDI by mixing 100 parts by weight of IPDI with 1 part by weight of tris (dimethylamino) phosphine at room temperature dimerized up to a conversion of approx. 40%; the unreacted IPDI and the catalyst are through separated by a thin film distillation.

The IPDI uretdione is then reacted with diols. Examples of such diols are

a) unveizweigte C ₂ -u-alkylene diols such as ethylene glycol, hexanediol-1,6, octanediol-1,8, and preferably 1,4-butanediol;

b) alkylene diols optionally substituted by alkyl groups and having a total of 3 to 14 carbon atoms, such as propylene-1,2- and -1,3-glycol, 2-ethylhexanediol-1,3, neopentyl glycol, 2-methylpropanediol and 3-methylpcn-

tandiol-1,5;

c) cycloaliphatic alkylene diols having 2 to 14 carbon atoms, such as l ^ -Bis-hydroxymethylcyclohexane, 3,8- and 4,9-bishydroxymethyltricyclo-tS ^ l.O ^ l-decane;

d) ether diols with up to 14 carbon atoms, such as diethylene glycol, triethylene glycol, tetraethylene glycol, Dipropy-S5 lenglycol and dibutylene glycol.

To implement the IPDI uretdione and the diol are mixed in the specified proportions. In general, the isocyanate component is initially introduced and the diol is added. The reaction can take place in substance or can be carried out in the presence of solvents. Suitable solvents are e.g. B.

Benzene, toluene, methyl or ethyl glycol acetate, dimethylformamide, xylene and other aromatic or aliphatic hydrocarbons; ketones, such as acetone, methyl isobutyl ketone and cyclohexanone, are also possible. The reaction takes place generally at temperatures from 50 to 12O ⁰ C. The reaction components are heated at the specified temperatures until all OH groups have reacted with the formation of urethane groups. This takes 0.5 to 5 hours, depending on the reaction temperature. It is also possible to use catalysts which accelerate isocyanate polyaddition; Organic tin compounds such as tin (II) acetate, dibutyltin dilaurate, dibutyltin maleate or dioelylzinndiaeelal are preferably used. The catalysts are generally used in an amount between 0.01 and 0.5 percent by weight, based on the total amount of the reactants used. The work-up takes place in the

As a rule, the polyurethane is freed from the solvent in vacuo. Particularly suitable melt extrusion in an evaporation screw is used to remove the solvent.

The hydroxyl-containing polyesters B to be used are converted in a manner known per se obtained from polycarboxylic acids, their anhydrides or their methyl esters with diols and / or polyols, where, by suitable choice of the COOH / OH ratio, hydroxyl numbers of the polyesters are between 10 and 200, S. preferably between 20 and 100 mg KOH / g can be achieved.

Usually one starts from cyclic polycarboxylic acids, in particular aromatic di- and tricarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, benzene-1,3,5-tricarboxylic acid, trimellitic anhydride or dimethyl terephthalate (DMT). Based on the total amount of acids, up to 20 percent by weight can be used also be replaced by aliphatic polycarboxylic acids with 4 to 14 carbon atoms. examples for this are Adipic acid, 2,2,4- and / or 2,4,4-trimethyladipic acid, sebacic acid and dodecanedioic acid.

The diols suitable for esterification include the same group that was used in the preparation of the IPDI uretdione addition compounds were listed.

As polyols, polyfunctional alcohols with up to 8 carbon atoms come into question, such as. B. glycerine, hexanetriol-1,2,3, Pentaerythritol, trimethylol propane and trimethylol ethane.

The softening temperatures of the polyester must be so low that they can be processed at temperatures between 70 and 12O ⁰ C with those used in the preparation of coatings additives. The melting point of the polyester is below 100 ^° C. On average, the polyesters contain more than 2 OH groups per molecule.

The polyester B and the hardener A are mixed in such proportions that there are 0.5 to 1.3, preferably 0.9 to 1.1, NCO equivalents of the hardener A per 1 OH equivalent of the polyester. It should be noted that hardener A in the uretdione form contains blocked NCO groups which are only released when exposed to heat. Under the amount of hardener, 1 NCO equivalent results, so that amount of hardener is understood that gives 42 g NCO after half an hour heating at 18O ⁰ C.

Leveling agents in quantities of 0.1 to 1 are added to the aforementioned binder combinations Part by weight, preferably 0.3 to 0.7 part by weight, usually as a polyacrylic acid ester, per 100 parts by weight of hardener and resin and pigments and optionally accelerators and fillers in the usual proportions, as used in coating powders, added.

These powder mixtures are ^{homogenized at 80 to 100 °} C. in extruders. The material, which becomes brittle on cooling, is ground and, if necessary, sieved, so that a powder with a grain size of less than 100 μίτι is obtained. This powder is by conventional powder spraying (EPS method electrostatic powder spraying), optionally pretreated to degreased and sprayed on steel panels and baked preferably 30 to 15 minutes at 180 to 200 ⁰ C.

1. Fabrication of the IPDI uretdione

100 parts by weight of IPDI were mixed with 1 part by weight of tris (dimethylamino) phosphine and left to stand at room temperature. After 20 hours when the NCO content had fallen to 31 percent by weight and had reacted thus about 40% of IPDI used, this mixture was subjected to thin film distillation at 130 ⁰ C and subjected mbar 12:13. The residue was catalyst-free and had an NCO content of 17.3%. If the residue was heated at 180 ° C. for 30 to 60 minutes, the NCO content rose to 37.3%. This so-called hot value is a measure of the content of uretdione groups in the reaction product.

2. Production of the hardener by reacting the IPDI uretdione with diols

2.1 640 parts by weight of IPDI uretdione prepared in 1 were dissolved in 500 parts by weight of anhydrous acetone and heated to 50 ⁰ C. After adding 1.1 g of dibutyltin dilaurate, 97.6 parts by weight of 1,4-butanediol were added dropwise to this solution over the course of one hour. The reaction mixture was then ^{heated at 50 °} C. for a further three hours. Acetone was then distilled off. To remove the last remains of acetone, the product was dried for eight hours in a vacuum drying cabinet at 60 ^° C. and 0.13 mbar. The reaction product had the following properties:

% NCO: 2.4

% NCO (after heating to 180 ^° C., previous year): 18.6

Mp ° C: 133-139

2.2 According to 2.1 there were 1282 parts by weight of the IPDI uretdione prepared in 1 and 202.7 parts by weight 1,4-butanediol used. The reaction product had the following properties:

% NCO: 1.4

% NCO (after heating to 180 ^° C., 1/2 h): 17.3

M.p. ° C: 142-148

2.3 According to 2.1, 700 parts by weight of the IPDI uretdione prepared in 1 and 130.5 parts by weight 1,4-butanedione implemented. The reaction product had the following properties:

% NCO: 0.2

% NCO (after heating to 180 ^° C., V2 h): 16.3

SmD ⁰ C: 165-173

3. Manufacture of polyester (■! ■

3.1 A mixture of 10.0 mol (1940 g) dimethyl terephthalate, 10.0 mol (1660.0 g) terephthalic acid, 10.5 mol |

(1092 g) 2 2-dimethylpropanediol-1,3, 2.9 moles (388.6 g) trimethylolpropane and 2 moles (288 g) 1,4-dime- | i

Ethylene cyclohexane and 6.25 moles (737.5 g) of 1,6-hexanediol were in a 5-1 glass flask with the aid of a $

Heated oil bath. After the materials were melted for the most part, was at a temperature of 16O ⁰ C ^ij 0.1 weight percent dimethyltin oxide added as an esterification catalyst. Within
For three hours, the sump temperature was slowly increased to 185 ° C. The further increase in temperature
a maximum of 230 ⁰ C sump temperature took place within a further 8 hours, with the heating

speed was based on the methanol / water separation. The polyester was then

cooled to 21O ⁰ C and largely removed by evacuation at 1.3 mbar of volatiles.
The bottom product was stirred cautiously throughout the condensation time. A stream of nitrogen
ensured a better discharge of methanol and water.

Physical data: g

OH number: 55 to 60 mg KOH / g U

Acid number: 2 to 4 mg KOH / g _; i

Melting point (Kofier): approx. 75 ° C |

Glass transition temperature (DTA): approx. 50 ⁰ C } ':

Viscosity at 16O ⁰ C: 25 000 mPa ■ s |

2 9 moles (1494 g) terephthalic acid, 9 moles (1746 g) dimethyl terephthalate, 3 moles (354.5 g) hexanediol-1,6, |

13 moles (1354 g) of neopentyl glycol, 3 moles (432 g) of 1,4-dimethylolcyclohexane and 1 mole (134 g) of methylol- g

propane were implemented as described under 3.1. The polyester obtained in this way had the following physical properties

lical properties: §§

OH number: 50 to 56 mg KOH / g |

Acid number: 3 to 4 mg KOH / g g

Melting point: approx. 70 ^° C.

Glass transition temperature (DTA): approx. 50 ⁰ C fl

Viscosity at 160 ^° C.: 12,000 mPa · sg

3 12 moles (1992 g) terephthalic acid, 12 moles (2328 g) dimethyl terephthalate, 5 moles (720 g) 1,4-dimethylolcyc- |

lohexane, 675 moles (796.5 g) hexanediol-1,6,11.5 moles (1196 g) neopentyl glycol, 3 moles (402 g) methylol- ||

propane were used as described under 3.1. The polyester obtained in this way had the following physical properties

ical properties:! §

OH number: 56 mg KOH / g g

Acid number: 3 mg KOH / g $

Melting point: 70 to 78 ⁰ C g

Glass transition temperature (DTA): 44 to 58 ° C | '

Viscosity at 160 ^° C.: 15,000 mPas jg

4. Production of the matt lacquer powder -g

The hardeners after 2 and polyester after 3 were combined with the pigments, leveling agents and accelerators in |

premixed to the specified weight ratios and homogenized in an extruder. G

The extrudates were crushed and ground. The particle size of the powder coating ingredients was smaller |

than 100 am These fine-grained mixtures were then by electrostatic powder spraying on degreased, &

if necessary, pretreated steel sheets are applied and then at the specified temperatures |

and times hardened. %

The properties of the paint films obtained were subjected to the following tests.

Example 4.1

The hardener was processed into a powder coating with white pigment (TiO ₂ ), the polyester as well as leveling agent *) and catalyst masterbatch **).

Composition of the powder coating:

47.90 percent by weight polyester according to Example 3.1

11.45 percent by weight hardener according to Example 2.1

40.0 percent by weight white pigment (TiO ₂ ) 5

0.50 weight percent polybutyl acrylate

0.15 weight percent dibutyl tin dilaurate

*) Liquid master batch:

lis 10 percent by weight of the leveling agent - a commercial copolymer of butyl acrylate and io 2-ethylhexyl acrylate - homogenized in the corresponding polyester in the melt and comminuted after solidification.

**) Catalyst masterbatch:

There are 5 percent by weight of the catalyst, e.g. B. dibutyltin dilaurate, homogenized in the corresponding polyester in the melt and comminuted after solidification. _{] 5}

After 15 minutes curing of the powder coating of the test sheets at 200 ⁰ C, the following results were obtained:

Layer thickness: 60 to 80 by 20

Gardner gloss level 60 ° (ASTM D 523): 18

Erichsen recess (DIN 53 156): 6.5 mm

Cross cut (DIN 53 151): Gt O

Mandrel bending test (DIN 53 152): <2 mm mandrel

Buchholz hardness (DIN 53 153): 100 25

Gardner direct impact (g ■ m):> 921.6

Example 4.2

(Analogous to example 4.1)

47.25 percent by weight polyester according to Example 3.1

12.10 percent by weight hardener according to Example 2.2

40.0 percent by weight white pigment (TiO ₂ ) 35

0.5 percent by weight leveling agent according to Example 4.1

0.15 percent by weight of catalyst according to Example 4.1

Lacquer technical characteristics:

Layer thickness: 65 to 75 μίτι

Gloss level according to Gardner 60 ° £ (ASTM D 523): 11

Erichsen depression (DlN 53 156): 5.1 mm

Cross cut (DIN 53 151): Gt O

Mandrel bending test (DIN 53 152): <2 mm mandrel 45

Buchholz hardness (DIN 53 153): 100

Gardner direct impact (g ■ m): 806.4

Example 4.3 50

(Analogous to example 4.1)

46.65 percent by weight polyester according to Example 3.1

12.70 percent by weight hardener according to Example 2.3 55

40.0 percent by weight white pigment (TiO ₂ )

0.5 percent by weight leveling agent according to Example 4.1

0.15 percent by weight of catalyst according to Example 4.1

Lacquer characteristics: 60

Layer thickness: 60 to 85 am

Gardner gloss level 60 ° <(ASTM D 523): 15

Erichsen depression (DlN 53 156): 4.7 mm

Grid section (DIN 53 151): Gt O 65

Mandrel bending test (DIN 53 152): <2 mm mandrel

Buchholz hardness (DIN 53 153): 100

Gardner direct impact (g m): 691.2

Example 4.4 (analogous to example 4.1)

48.25 percent by weight polyester according to Example 3.2

11.10 percent by weight hardener according to Example 2.1

40.0 percent by weight white pigment (TiO ₂ )

0.5 percent by weight leveling agent according to Example 4.1

0.15 percent by weight of catalyst according to Example 4.1

Lacquer technical characteristics:

Layer thickness: 65 to 80 μm

Gardner gloss level 60 ° <(ASTM D 523): 36

15 Erichsen recess (DIN 53 156): 8.8 mm

Cross cut (DIN 53 151): Gt

Mandrel bending test (DIN 53 152): <2 mm mandrel

Buchholz hardness (DIN 53 153):

Gardner direct impact (g m):> 921.6

Example 4.5 (analogous to example 4.1)

47.55 percent by weight polyester according to example 3.2 11.80 percent by weight hardener according to example 2.2 40.0 percent by weight white pigment (TiO ₂ ) 0.50 percent by weight leveling agent according to example 4.1 0.15 percent by weight catalyst according to example 4.1

Lacquer technical characteristics:

Layer thickness: 65 to 85 μm

Gardner gloss level 60 ° £ (ASTM D 523): 31

Erichsen recess (DIN 53 156): 7.2 mm

Cross cut (DIN 53 151): Gt

Buchholz hardness (DIN 53 153):

Mandrel bending test (DIN 53 152): <2 mm mandrel

40 Gardner direct impact (g m): 806.4

Example 4.6 45 (analogous to example 4.1)

46.95 percent by weight polyester according to example 3.2 12.40 percent by weight hardener according to example 2.3 40.0 percent by weight white pigment (TiO ₂ ) 0.5 percent by weight leveling agent according to example 4.1 0.15 percent by weight catalyst according to example 4.1

Lacquer technical characteristics:

55 Layer thickness: 65 to 75 μm

Gardner gloss level 60 ° (ASTM D 523): 28

Erichsen recess (DIN 53 156): 6.5 mm

Cross cut (DIN 53 151): Gt O

Mandrel bending test (DIN 53 152): <2 mm dome

Buchholz hardness (DIN 53 153):

Gardner direct impact (g m): 806.4

Layer thickness: 60 um 7.8 mm Gardner gloss level 60 ° <* (ASTM D 523): 12 GtO Erichsen depression (DIN 53 156): <2 mm dome Cross cut (DIN 53 151): 111 Mandrel bending test (DIN 53 152): Gardner direct impact (g ■ m):> 921.6 Buchholz hardness (DIN 53 153): Example 4.8 (Analogous to example 4.1)

Example 4.7
(Analogous to example 4.1)

48.25 percent by weight polyester according to Example 3.3 5

11.10 percent by weight hardener according to example 2.1
40.0 percent by weight white pigment (TiO ₂ )

0.5 percent by weight leveling agent according to Example 4.1

0.15 percent by weight of catalyst according to Example 4.1

Lacquer technical characteristics:

47.55 percent by weight polyester according to Example 3.3
11.80 percent by weight hardener according to Example 2.2
40.0 percent by weight white pigment (TiO ₂ )

0.5 percent by weight leveling agent according to Example 4.1

0.15 percent by weight of catalyst according to Example 4.1 30

Lacquer technical characteristics:

Layer thickness: 65 μm

Gardner gloss level 60 ° <(ASTM D 523): 12 35

Erichsen recess (DIN 53 156): 9.0 mm

Cross cut (DIN 53 151): Gt O

Mandrel bending test (DIN 53 152): <2 mm mandrel

Buchholz hardness (DIN 53 153): 100

Gardner direct impact (g ■ m):> 921.6 40

Example 4.9
(Analogous to example 4.1) 45

46.97 percent by weight polyester according to Example 3.3

12.38 percent by weight hardener according to Example 2.3

40.0 percent by weight white pigment (TiO ₂ )

0.5 percent by weight leveling agent according to Example 4.1 50

0.15 percent by weight of catalyst according to Example 4.1

Lacquer technical characteristics:

Layer thickness: 60 μm 55

Gloss level according to Gardner 60 ° <(ASTM D 523): 11

Erichsen depression (DIN 53 156): 8.8 mm

Cross cut (DIN 53 151): Gt O

Mandrel bending test (DIN 53 152): <2 mm mandrel

Buchholz hardness (DIN 53 153): 111 6C

Gardner direct impact (g m):> 921.6

Claims (1)

10 202530354045 claims: 1. Storage-stable powder coatings with a grain size smaller than 100 μΐη based on a mixture of substances, consisting of A polyisocyanates, B polyols, C as well as usual additives,